Piston and connecting rod
- 1. Piston rings
- 2. Piston
- 3. Piston pin
- 4. Retaining ring
- 5. Connecting rod
- 6. Connecting rod bearing
- 7. Cylinder block
- 8. Connecting rod cap
- 9. Mounting pin
- 10. Oil jet
- 11. Oil jet screw
- 12. Connecting rod cap bolts
- A - identification marks on the connecting rod and connecting rod cap
- B - orientation marks
Piston and connecting rod
Removal
1. Remove the cylinder head, flywheel, oil pan, oil pump and oil pick-up pipe.
2. Remove the ledge on the top of the cylinder caused by wear.
3. If the connecting rods and connecting rod caps are not marked, mark them.
4. Set pistons N1 and N4 to bottom dead center.
5. Unscrew the fastening nuts and remove the first connecting rod cover and bearing shell, mark the shells.
6. Place pieces of rubber tubing over the connecting rod bolts to avoid damaging the crankshaft journal and cylinder walls.
7. Remove the bearing shell and lift the connecting rod out from the top of the cylinder block.
8. Remove the remaining connecting rods and pistons in the same manner.
9. If possible, unscrew the screws and remove the piston jets.
Piston head (AAT)
Examination
1. Use a small screwdriver to remove the piston pin retaining rings and remove the pin. Inspect the pin for wear and damage; if damage is found, contact a specialist.
2. Remove the piston rings. Clean the piston crown from deposits and clean the piston ring grooves. After removing all deposits. Clean the pistons and connecting rods with solvent and dry them.
3. Carefully inspect all pistons for cracks in the piston skirt and around the connecting rod pin. Inspect pistons for scratches, scoring, burnt areas, or corrosion.
4. Inspect the connecting rods for cracks and other damage. For a more detailed inspection of pistons and connecting rods, contact specialists
5. Measure the diameters of all four pistons.
6. Measure the piston ring side clearance.
7. When assembling the piston and connecting rod, note that the arrow on the piston head should point towards the timing belt. The marks on the connecting rod and on the connecting rod cap should point towards the turbocharger.
Checking the lubrication clearance of connecting rod bearings
To measure the lubrication gap, you can use an internal micrometer or other special device, but the most accurate and easiest method is to use a special plastic gauge.
Temporarily install the piston in the cylinder, tighten the connecting rod cap bolts, and check the connecting rod bearing lubrication clearance in the same way as checking the main bearing lubrication clearance.
If the gap size is not as required, the bearing shells may be the wrong size.
Piston arrangement and coding in diesel engines
Final installation of pistons and connecting rods
1. Remove all traces of plastic. Check that the surface of the bearings is absolutely clean and lubricate them with engine oil.
2. Clean the upper connecting rod bearing shell and install it on the connecting rod. The oil holes in the connecting rod and the shell must be aligned.
3. Clean the second bearing and install it into the connecting rod cap.
4. Lubricate the pistons and rings and compress the piston rings using a piston ring compressor.
5. Turn the crankshaft so that the connecting rod bearing of the first cylinder is at the bottom dead center position and lubricate the cylinder walls.
6. Make sure the mark on the top of the piston is facing forward.
7. Press the piston and install it into the cylinder.
8. The installation of the remaining connecting rods is carried out in a similar manner.
9. Install the connecting rod onto the crankshaft journal and install the connecting rod cap.
- A - pin (diesel only)
- B - mounting hole (diesel only)
10. In diesel 4-cylinder engines 1Z and AHU and 5-cylinder ABP, AAT, AEL pistons have a special shape for better combustion of the mixture and must be installed correctly (see fig. Piston arrangement and coding in diesel engines).
11. Tighten the bolts to the specified torque.
12. Tighten the bolts to the required angle.
13. After installing all connecting rods, turn the crankshaft several times and check for ease of movement.
Diesel engines 1Z, AHU, AAS, ABP, AAT, AEL
13. To accurately select the gasket thickness, measure the piston protrusions using a special tool.